Analysis histamine

Two ml of aqueous extract followed and the eluent discarded. Two additional ml of the plant extract were then passed through the Sep-Pak and retained for HPLC analysis. Histamine is not retained on the packing and will always remain in the liquid fraction. 

Several methods were reported for the analysis of histamine, but the fluorimetric determination with o-phthaldialdehyde (OPA) the most widely used. It was shown that adducts, formed in the reaction of histamine with OPA in the presence of reducing agent, is more stable and gives high relative fluorescence intensity. The influences of different tiols on the fluorimeric determination histamine with OPA have been investigated. 

The derivatives have an optimum fluorescence at an excitation wavelength of 340 nm and an emission wavelength of 455 nm. The adduct is relatively stable at a pH of 9-11 but it rapidly degrades to a non-fluorescent residue at low pH values. Consequently, when used as a pre-column derivatizing reagent the pH of the mobile phase should be kept fairly high, o-phthalaldehyde has been employed for derivatization in the analysis of dopamine (29), catecholamines (30) and histamines (31). 

The detection of reactions mediated by specific IgE to agents triggering anaphylaxis may be achieved by means of serological methods serum-specific IgE, or by means of cellular tests which determine the release of basophil mediators (leukotrienes and histamine) or by means of the analysis of basophil expression markers, a technique known as the basophil activation test (BAT). 

As immediately after the reaction, elevated plasma histamine and serum or plasma tryptase levels of histamine and tryptase have been found [31, 34], an anaphylaxis may be confirmed by blood samples for histamine analysis drawn as soon as possible after the reaction and for tryptase drawn 1-2 h after onset of symptoms [31]. Tryptase values have to be compared to baseline levels. 

As a consequence of the inhalation of mineral dusts, infiltration into the lung of inflammatory phagocytic cells, namely PMN and macrophages, occurs (Rola-Pleszczynski et al., 1984). Analysis of the cell populations of the rat pleural cavities after injection with asbestos and silica dust also showed both degranulation and reduction of the mast cell population (Edwards etal., 1984), and it is of interest to note that histamine augments the particle-stimulated generation of macrophage superoxide production (Diaz et al., 1979). 

Applying the analysis in the left-hand column to the results of Figure 1.24, Furchgott estimated Ka to be 10 pM for the combination of histamine with its receptors. He used this figure, and the values of q obtained as just described, to construct the dashed curves in the illustration. These lie close to the experimental points, which is certainly in keeping with the predictions of the approach taken. Just as certainly, this does not provide decisive proof that either the experimental or the theoretical suppositions that underlie it are correct. An important assumption, and one that is difficult to test, is that the irreversible antagonist has had no action other than to inactivate the receptors under study. Were it, for example, to have interfered with one or more of the steps that link receptor activation to the observed response, the approach would be invalid. Furchgott later showed that this was not a complication under the conditions he used. 

Black, J. W., Leff, R, and Shankley, N. R, Further analysis of anomalous pXj values for histamine H2-receptor antagonists on the mouse isolated stomach assay, Br. J. Pharmacol., 86, 581-587, 1985. 

In the same article data set was expanded to include some 20 potent histamine H2 antagonists. Analysis of these compounds indicated the significance of lipophilicity and hydrogen bonding for penetration of BBB, since a good... 

Biogenic amines are of great interest to researchers because of their potential roles in several psychiatric and neurological disorders. They include dopamine (DA), noradrenaline (NA), 5-hydroxytryptamine (5-HT, serotonin), histamine, and trace amines such as 2-phenylethylamine (PEA), tyramine, octopamine, phenylethanolamine, and tryptamine (Coutts and Baker, 1982). Although GC assays for DA, NA, and 5-HT are available, HPLC analysis with electrochemical detection has for many years now been the method of choice for analysis of these neurotransmitter amines. 

Diaz-Cinco, M.E., Fraijo, O., Grajeda, P., Lozano-Taylor, X. and Gonzalez de Mejia, E. (1992). Microbial and chemical analysis of Chihuahua cheese and relationship to histamine and tyramine, J. Food Sci., 57, 355. 

HPLC analysis was performed on 20-50 ul of these extracts with the volume of injection dependent upon the concentration of histamine. Each histamine value represents the mean of three trials to obtain a determination with a 95% confidence level. 

HPLC Separation of Histamine. There are three possibilities for separation of histamine by HPLC normal phase on silica, reversed phase on a bonded silica column, or an ion-exchange separation. Perini (16) demonstrated that a cation-exchange separation is possible, but the analysis time was lengthy for examination of histamine in animal biofluids (70 min). Histamine is freely soluble in water, is slightly soluble in hot chloroform, and is insoluble in less polar solvents, making a... 

The HPLC method presented is based upon the separation of histamine itself and not a derivative of unknown structure. An ion-pair model is proposed to control retention of histamine on bonded phase columns. This method and model should be applicable to a wide range of biosystems, as well as other aqueous plant extracts. Our results determined by HPLC analysis agree closely with those obtained previously using biological methods but provide geater reproducibility and simplicity. 

Fruit juices such as grapefruit, orange, and apple may reduce the bioavailability and exposure of fexofenadine. This is based on the results from three clinical studies using histamine-induced skin wheals and flares coupled with population pharmacokinetic analysis. Therefore, to maximize the effects of fexofenadine, it is recommended that ALLEGRA-D 24 HOUR should be taken with water... 

Fales and Pisano (30) were the first to describe the gas chromatographic analysis of amphetamine. They used 4% SE-30 in a silanized glass column and an argon ionization detector for the separation of (3-phenethylamine, amphetamine, norephedrine, eph drine, histamine, tyramine, dimethyltriptamine, tryptamine, 5-methoxytryptamine, benzylamine, N-methylbenzylamine, octopamine, synephrine, normetanephrine, serotonin, N-acetyltryptamine, find melatonin. The method was also used for the analysis of amphetamine extracted from urine. 

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